1. Field of the Invention
The present invention relates to implantable prostheses. More particularly, the present invention relates to implantable breast prostheses designed to eliminate encapsulation and reduce scarring, and to replace tissue removed for purposes of biopsy or lumpectomy.
2. Description of the Related Art
Breast prostheses are utilized for augmentation mammoplasty and in cosmetic surgery. Prostheses also are indicated in breast cancer surgery, such as lumpectomies, where a portion of the breast is removed and can leave some disfigurement if not replaced by a similar amount of tissue and/or augmentation material.
Similarly, biopsies can leave small dimples or imperfections if remedial steps are not taken. About 1 million breast biopsies are performed in the United States annually. As a result, some 200,000 new breast cancers are diagnosed each year.
Known methods of augmentation mammoplasty utilize silicone or saline implants. These methods have been complicated post-operatively by encapsulation of the implants, which can occur to varying degrees. Encapsulation produces a hard area of scar tissue around the implant, resulting in a rigid, abnormally-shaped mound beneath the breast tissue or pectoralis muscle, depending upon the placement of the implant.
Moreover, the known implant materials may not be indicated for replacement of smaller amounts of tissue, as would be required to prevent dimpling after biopsies, for example. Further, the known implant materials are not amenable to resizing. In addition, known implants are not capable of being implanted through a cannula or needle, and are not readily instilled with medicaments or chemical agents that would be useful in treating the patient.
Accordingly, a need exists for implants and methods that can be adapted for replacement of small as well as large amounts of tissue. A need also exists for implants that can be delivered through cannulae or needles, as well as being able to significantly reduce or eliminate encapsulation, resulting in a prolonged, aesthetically pleasing, soft mound below the breast tissue or pectoralis muscle. In addition, a need exists for implants into which useful substances, such as beneficial medications, chemical agents, hormonal treatments, stem cells, such as adipocytes, cellular precursors and components, and radiation media can be instilled to enhance the treatment capabilities of the implant in cancer and other breast pathology.
The present invention overcomes deficiencies of the prior art, such as those noted above, by providing an implant in which at least the outer portion of the implant, and as much as the entire implant, is made of a resorbable material. The implant is sized and shaped to replace excised tissue. Preferably, the implant provides a support structure in the form of a framework or scaffold for the surrounding tissue after implantation. The support structure preferably is porous to permit the in-growth of fibrous replacement tissue. Advantageously, replacement tissue in-growth takes place without encapsulation and with reduced scarring.
According to an embodiment of the invention, excised tissue is replaced by installing an implant having at least an outer shell of resorbable material. The implant is sized and shaped to replace the excised tissue. The implant supports surrounding tissue while fibrous tissue replaces the resorbable portion of the implant.
In a further development, at least a portion of the implant can be provided in the form of a compressible or non-compressible sponge or foam, or a self-expanding sponge or foam. The sponge or foam provides a porous support matrix for surrounding and in-growing tissue. In the form of a compressible, expandable, or self-expanding sponge or foam, the implant advantageously can be inserted through a cannula or a needle, or optionally can be directly inserted. Additionally, the implant can be instilled with beneficial materials, such as indicated medicaments, therapeutics, or diagnostic agents, as well as matrix enhancing additives.
Other features and advantages of the present invention will become apparent from the following description of the invention which refers to the accompanying drawings.